“…However, the most significant limitations of these techniques are typically very time consuming, expensive, require skilled technicians, off-site analyses, and matrix-matched calibration standards that are not routinely determined [14]. To overcome these issues, various other techniques have been considered to detect hydrogen, e.g., electrochemical [15], catalyst [16], resistance based [17], and optical methods [18][19][20]. However, electrochemical and optical based sensors are the most preferred because they are capable of detecting low concentrations of hydrogen with an acceptable selectivity [3,21].…”